She’s been in custody since last summer, when she allegedly threw her developmentally disabled 7-month son off the roof of the Children’s Hospital of Orange County.

Hermosillo was in court for an arraignment hearing, but she did not make a plea.

Her attorney, Jacqueline Goodman, says she’s moving ahead on two fronts: To file a motion to get the murder charge dismissed because of a lack of evidence presented at the preliminary hearing; and to have her client plead not guilty by reason of insanity.

“Her plea, should it prevail, would result in a not-guilty judgment, based on the fact her sanity is what motivated whatever action or accident took place,” Goodman said.

All along, this horrific case has been about mental illness.

Earlier this year, three court-appointed psychologists disagreed on Hermosillo’s competency to stand trial, but a judge ordered it to proceed.

Hermosillo’s husband, who came to see his wife in court Tuesday, has said his wife suffered from severe post-partum depression after their son was born.

Goodman said the family was desperately trying to get her psychiatric help prior to the incident.

She says this case and last week’s massacre in Connecticut both demonstrate that we ignore mental illness at our peril.

“I’m not making the argument that people aren’t responsible for their actions," said Goodman, "but at some point you have to realize that if we ignore the issue of mental illness, the ramifications of that are grave. If we can give people who have a mental illness the kind of help they need, I think we should. I don’t know how we cannot.”

Goodman says Hermosillo still doesn’t comprehend what she did.

Prosecutors say otherwise. They cite the fact that Hermosillo removed her son’s protective helmet before throwing him from the roof as evidence she knew what she was doing.